The two-dimensional B-splines of the 3rd degree are used. The file contains a 3D array over dimensions longitude, latitude, component. The first index runs in the range [-2,Nlon+2], the second runs in the range [-2,Nlat], and the third runs in the range [1,3], where Nlon=10800, and Nlat=5401. The original grid runs from 0° through 359°58′ over longitude and -90° through +90° over latitude. In order to avoid errors in interpolation near the 0° meridian, the original grid is augmented by two nodes over longitude: 0° through 360°02′.
The two-dimensional B-spline is computed at the extended sequence of knots that starts with index -2. The first three knots have multiplicity three, or using another language their arguments is equal. The B-spline is normalized over unity: ∑ B_{i}(x) = 1.0
The third dimension runs over the components of the displacement field: up, east, north.
The two-dimensional B-splines of the 3rd degree are used. The file contains a 4D array over dimensions longitude, latitude, displacement component, harmonic component. The first index runs in the range [-2,Nlon+2], the second runs in the range [-2,Nlat], and the third runs in the range [1,3], and the fourth runs over [1, 2Nfreq], where Nlon=10800, and Nlat=5401. The original grid runs from 0° through 359°58′ over longitude and -90° through +90° over latitude. The harmonics component is either the cosine or sine amplitude for a given frequency. In order to avoid errors in interpolation near the 0° meridian, the original grid is augmented by two nodes over longitude: 0° through 360°02′. The meaning and order of frequency components is described in the metadata parameter SDS_name.
The two-dimensional B-spline is computed at the extended sequence of knots that starts with index -2. The first three knots have multiplicity three, or using another language their arguments is equal. The B-spline is normalized over unity: ∑ B_{i}(x) = 1.0
The third dimension runs over the components of the displacement field: up, east, north.